Optical sensor for a monitoring device

ABSTRACT

An optical sensor for a monitoring device for monitoring the vital signs of a user is disclosed herein. The optical sensor preferably includes a photodetector and a two light emitting diodes (“LEDs”) that emit green light. The optical sensor includes a light barrier that includes multiple walls that block any non-reflected light from the LEDs from transmission to the photodetector so that the photodetector only receives light reflected from the artery of the user resulting in a more accurate detection of the heart rate of the user. A sensor signal from the optical sensor is processed with an accelerometer output signal from the accelerometer to generate a real-time vital sign for a user.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 13/312,935, filed Dec. 6, 2011, which is acontinuation of U.S. patent application Ser. No. 13/253,046, filed onOct. 4, 2011, which claims priority to U.S. Provisional PatentApplication No. 61/408,656, filed on Nov. 1, 2010, and U.S. ProvisionalPatent Application No. 61/394,744, filed on Oct. 19, 2010. The PresentApplication is also a continuation-in-part application of U.S. patentapplication Ser. No. 13/191,907, filed on Jul. 27, 2011, which claimspriority to U.S. Provisional Patent Application No. 61/368,262, filedJul. 28, 2010. The present application is also a continuation-in-partapplication of U.S. patent application Ser. No. 12/561,222, filed onSep. 16, 2009, which claims priority to U.S. Provisional PatentApplication No. 61/097,844, filed on Sep. 17, 2008, and which is acontinuation-in-part application of U.S. patent application Ser. No.11/856,056, filed Sep. 16, 2007, now U.S. Pat. No. 7,625,344, which is acontinuation application of U.S. patent application Ser. No. 11/762,078,filed on Jun. 13, 2007, now U.S. Pat. No. 7,468,036, and which is also acontinuation-in-part application of U.S. patent application Ser. No.11/388,707, filed on Mar. 24, 2006, which claims priority to U.S.Provisional Application No. 60/665,116, filed on Mar. 25, 2005, andwhich is also a continuation-in-part application of U.S. patentapplication Ser. No. 11/085,778, filed on Mar. 21, 2005, now abandoned,which claims priority to U.S. Provisional Application No. 60/613,785,filed on Sep. 28, 2004. All of the above mentioned applications arehereby incorporated by reference in their entireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to real-time vital sign monitoringdevices. More specifically, the present invention relates to a devicefor monitoring a user's vital signs that is used in conjunction with aSmartphone.

2. Description of the Related Art

There is a need to know how one is doing from a health perspective. Insome individuals, there is a daily, even hourly, need to know one'shealth. The prior art has provided some devices to meet this need.

One such device is a pulse oximetry device. Pulse oximetry is used todetermine the oxygen saturation of arterial blood. Pulse oximeterdevices typically contain two light emitting diodes: one in the red bandof light (660 nanometers) and one in the infrared band of light (940nanometers). Oxyhemoglobin absorbs infrared light while deoxyhemoglobinabsorbs visible red light. Pulse oximeter devices also contain sensorsthat detect the ratio of red/infrared absorption several hundred timesper second. A preferred algorithm for calculating the absorption isderived from the Beer-Lambert Law, which determines the transmittedlight from the incident light multiplied by the exponential of thenegative of the product of the distance through the medium, theconcentration of the solute and the extinction coefficient of thesolute.

The major advantages of pulse oximetry devices include the fact that thedevices are non-invasive, easy to use, allows for continuous monitoring,permits early detection of desaturation and is relatively inexpensive.The disadvantages of pulse oximetry devices are that it is prone toartifact, it is inaccurate at saturation levels below 70%, and there isa minimal risk of burns in poor perfusion states. Several factors cancause inaccurate readings using pulse oximetry including ambient light,deep skin pigment, excessive motion, fingernail polish, low flow causedby cardiac bypass, hypotension, vasoconstriction, and the like.

In monitoring one's health there is a constant need to know how manycalories have been expended whether exercising or going about one'sdaily routine. A calorie is a measure of heat, generated when energy isproduced in our bodies. The amount of calories burned during exercise isa measure of the total amount of energy used during a workout. This canbe important, since increased energy usage through exercise helps reducebody fat. There are several means to measure this expenditure of energy.To calculate the calories burned during exercise one multiplies theintensity level of the exercise by one's body weight (in kilograms).This provides the amount of calories burned in an hour. A unit ofmeasurement called a MET is used to rate the intensity of an exercise.One MET is equal to the amount of energy expended at rest.

For example, the intensity of walking 3 miles per hour (“mph”) is about3.3 METS. At this speed, a person who weighs 132 pounds (60 kilograms)will burn about 200 calories per hour (60×3.3=198).

The computer controls in higher-quality exercise equipment can provide acalculation of how many calories are burned by an individual using theequipment. Based on the workload, the computer controls of the equipmentcalculate exercise intensity and calories burned according toestablished formulae.

The readings provided by equipment are only accurate if one is able toinput one's body weight. If the machine does not allow this, then the“calories per hour” or “calories used” displays are only approximations.The machines have built-in standard weights (usually 174 pounds) thatare used when there is no specific user weight. There are devices thatutilize a watch-type monitor to provide the wearer with heart rate asmeasured by a heartbeat sensor in a chest belt.

However, the prior art devices often suffer from noise, light and motionrelated problems. These problems are increased when the userparticipates in an athletic activity such as running. Further,attempting to correct one problem often creates additional problems suchas increasing a sensor output which results in a shorter battery life.The prior art has failed to provide a means for monitoring one's healththat is accurate, easy to wear on one's body for extended time periods,allows the user to input information and control the output, andprovides sufficient information to the user about the user's health.Thus, there is a need for a monitoring device that can be worn for anextended period and provide health information to a user.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a solution to the shortcomings of theprior art. The present invention is accurate, comfortable to wear by auser for extended time periods, allows for input and controlled outputby the user, is light weight, and provides sufficient real-timeinformation to the user about the user's health.

One aspect of the present invention is a method for monitoring areal-time vital sign of a user by using a signal from an optical sensorand a signal from a multiple axis accelerometer that generates an X-axissignal, a Y-axis signal and a Z-axis signal.

Another aspect of the present invention is of the present invention is asystem for monitoring a real-time vital sign of a user. The system formonitoring a real-time vital sign of a user comprises a monitoringdevice comprising an optical sensor for generating a real-time digitizedoptical signal corresponding to a flow of blood through an artery of theuser and an accelerometer for generating real-time accelerometer datacomprising a X-axis signal, a Y-axis signal and a Z-axis signal based ona movement of the user. The system further comprises a first transceiverfor transmitting the real-time digitized optical signal and thereal-time accelerometer data from the monitoring device. Additionally,the system comprises a mobile communication device comprising a secondtransceiver for receiving the real-time digitized optical signal and thereal-time accelerometer data from the monitoring device. Additionally,the system comprises a processor in electrical communication with thesecond transceiver, the processor configured to receive the real-timedigitized signal and the real-time accelerometer data, the processorconfigured to calculate a period of motion related harmonics from thereal-time accelerometer data utilizing a repetitive motion patternanalyzer, the processor configured to modify the real-time digitizedoptical signal by suppressing the motion related harmonics calculated bythe motion pattern analyzer to generate a modified optical signal, theprocessor configured to generate a real-time heart rate for the userfrom the modified optical signal,

Optionally, the modified optical signal is filtered with a narrow bandfilter adaptively tuned to a heart rate frequency calculated by a heartrate evaluator to generate the real-time heart rate for the user.Preferably, the repetitive motion pattern analyzer comprises an array ofComb filters. Preferably, the optical sensor comprises two green LEDsand a photodetector.

Having briefly described the present invention, the above and furtherobjects, features and advantages thereof will be recognized by thoseskilled in the pertinent art from the following detailed description ofthe invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a plan view of a preferred embodiment of a monitoring deviceworn by a user.

FIG. 2 is a side view of a monitoring device.

FIG. 3 is an interior surface plan view of a monitoring device.

FIG. 4 is a side view of a monitoring device.

FIG. 5 is an exterior surface view of a monitoring device.

FIG. 6 is an isolated view of the electrical components of a monitoringdevice.

FIG. 7 is isolated side view of the electrical components of amonitoring device.

FIG. 8 is an isolated exterior surface view of an optical sensor for amonitoring device.

FIG. 9 is an isolated top plan view of an optical sensor for amonitoring device.

FIG. 10 is an isolated cross section view of an optical sensor for amonitoring device.

FIG. 11 is an isolated cross section view of an optical sensor for amonitoring device with light reflecting off of an artery of a user.

FIG. 12 is a block diagram of electrical components for a monitoringdevice.

FIG. 13 is a block diagram of signal processing for a monitoring device.

FIG. 14 is a schematic flow chart of the signal acquisition step of theflow chart of FIG. 13.

FIG. 15 is an illustration of the waveforms of the data sampling duringthe signal processing method.

FIG. 16 is a graph illustrating the method and mechanism of controllingthe intensity of the light source over time.

FIG. 17 is a flow chart of a signal processing method of the presentinvention.

FIG. 18 is a block diagram of signal processing for a monitoring device.

FIG. 19 is a block diagram of signal processing of a prior art device.

FIG. 20 is a block diagram of signal processing for a monitoring device.

FIG. 21 is a block diagram of a comb filter type 2 for signalprocessing.

FIG. 22 is a block diagram of a comb filter type 1 for signalprocessing.

FIG. 23 is a block diagram of a four-cycle comb filter type 1 with afilter delay for signal processing.

FIG. 24 is a block diagram of a four-cycle comb filter type 1 with afilter delay for signal processing.

FIG. 25 is a block diagram of a mobile communication device such as amobile phone.

FIG. 26 is an illustration of a system including a monitoring device anda mobile phone which receives a signal from the monitoring device.

FIG. 27 is an illustration of a runner with a monitoring device and amobile phone.

FIG. 28 is an isolated view of a mobile phone with a display ofinformation generated from a signal from a monitoring device.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-5, a monitoring device is generally designated 20.The monitoring device 20 preferably includes an article 25 and anattachment band 26 having an exterior surface 26 a and interior surface26 b. The monitoring device 20 is preferably secured with VELCRO® hookand loop material 31 a and 31 b. The article 25 preferably includes anoptical sensor 30, control components 43 a-43 c and optionally a displaymember 40. The monitoring device 20 is preferably worn on a user'swrist, arm or ankle.

The article 25 preferably has a USB port for a wired connection to acomputer, tablet, video monitor or mobile communication device such assmartphone.

It is desirous to adapt the monitoring device 20 to the anatomy of theuser's arm or even the user's ankle. The band 26 is preferably composedof neoprene, leather, synthetic leather, LYCRA, another similarmaterial, or a combination thereof. The article 25 is preferablycomposed of a semi-rigid or rigid plastic with a rubber-like orsemi-flex plastic bottom layer for contact with the user's body. Thebottom layer of the article 25 may have a curve surface for contact witha user's body. The article 25 preferably has a mass ranging from 5 gramsto 50 grams. Preferably, the lower the mass of the article 25, the morecomfort to the user. The article 25 preferably has a thickness rangingfrom 5 mm to 10 mm, and is most preferably 6.5 mm.

Although the monitoring device 20 is described in reference to anarticle worn on a user's arm, wrist or ankle, those skilled in thepertinent art will recognize that the monitoring device 20 may takeother forms such as eyewear disclosed in Brady et al, U.S. Pat. No.7,648,463, for a Monitoring Device, Method And System, which is herebyincorporated by reference in its entirety or a glove such as disclosedin Rulkov et al., U.S. Pat. No. 7,887,492, for a Monitoring Device,Method And System, which is hereby incorporated by reference in itsentirety.

The optical sensor 30 of the monitoring device 20 is preferablypositioned over the radial artery or ulnar artery if the article 25 isworn on the user's arm. The optical sensor 30 of the monitoring device20 is preferably positioned over the posterior tibial artery of a userif the article 25 is worn on the user's ankle. However, those skilled inthe pertinent art will recognize that the optical sensor may be placedover other arteries of the user without departing from the scope andspirit of the present invention. Further, the optical sensor 30 needonly be in proximity to an artery of the user in order to obtain areading or signal.

In a preferred embodiment, the optical sensor 30 is a plurality of lightemitting diodes (“LED”) 35 based on green light wherein the LEDs 35generate green light (wavelength of 500-570 nm), and a photodetector 36detects the green light. Yet in an alternative embodiment, the opticalsensor 30 is a photodetector 36 and a single LED 35 transmitting lightat a wavelength of approximately 900 nanometers as a pulsed infraredLED. Yet further, the optical sensor is a combination of a green lightLED and a pulsed infrared LED to offset noise affects of ambient lightand sunlight. As the heart pumps blood through the arteries in theuser's arm, ankle or wrist, the photodetector 36, which is typically aphotodiode, detects reflectance/transmission at the wavelengths (green,red or infrared), and in response generates a radiation-induced signal.

A preferred optical sensor 30 utilizing green light is a TRS1755 sensorfrom TAOS, Inc of Plano Tex. The TRS1755 comprises a green LED lightsource (567 nm wavelength) and a light-to-voltage converter. The outputvoltage is directly proportional to the reflected light intensity.Another preferred photodetector 36 is a light-to-voltage photodetectorsuch as the TSL260R and TSL261, TSL261R photodetectors available fromTAOS, Inc of Plano Tex. Alternatively, the photodetector 130 is alight-to-frequency photodetector such as the TSL245R, which is alsoavailable from TAOS, Inc. The light-to-voltage photodetectors have anintegrated transimpedance amplifier on a single monolithic integratedcircuit, which reduces the need for ambient light filtering. The TSL261photodetector preferably operates at a wavelength greater than 750nanometers, and optimally at 940 nanometers, which would preferably havea LED that radiates light at those wavelengths.

In one embodiment, discussed below, the display member 40 is removed andthe signal is sent to a device such as a personal digital assistant,laptop computer, mobile telephone, exercise equipment, or the like fordisplay and even processing of the user's real-time vital signsinformation. Alternatively, the circuitry assembly includes a flexiblemicroprocessor board which is a low power, micro-size easily integratedboard which provides blood oxygenation level, pulse rate (heart rate),signal strength bargraph, plethysmogram and status bits data. Themicroprocessor can also store data. The microprocessor can process thedata to display pulse rate, blood oxygenation levels, calories expendedby the user of a pre-set time period, target zone activity, time anddynamic blood pressure. Further, microprocessor preferably includes anautomatic gain control for preventing saturation of the photodetector,which allows for the device to be used on different portions of thehuman body.

The display member 40 is preferably a light emitting diode (“LED”).Alternatively, the display member 40 is a liquid crystal display (“LCD”)or other similar display device.

A microprocessor processes the signal generated from the optical sensor30 to generate the plurality of vital sign information for the userwhich is displayed on the display member 40. The control components 43a-c are connected to the processor to control the input of informationand the output of information displayed on the display member 40.

The monitoring device 20 is preferably powered by a power sourcepositioned on the article 25. Preferably the power source is a battery.The power source 360 is preferably an AA or AAA disposable orrechargeable battery. The power source is alternatively a lithium ionrechargeable battery such as available from NEC-Tokin. The power sourcepreferably has an accessible port for recharging. The circuit assemblyof the monitoring device preferably requires 5 volts and draws a currentof 20-to 40 milliamps. The power source preferably provides at least 900milliamp hours of power to the monitoring device 20.

A connection wire arrangement 45 is shown in FIGS. 6 and 8, wherein theconnection 45 between the microprocessor and the optical sensor 30 ispreferably non-planar or non-straight in order to reduce noise in thesignal. The optical sensor 30 preferably comprises a photodetector 36,and first and second LEDs 35 which transmit light. Using two LEDs oneach side of a photodetector creates a more mechanically stable opticalsensor 30.

The monitoring device 20 alternatively has a short-range wirelesstransceiver which is preferably a transmitter operating on a wirelessprotocol, e.g. BLUETOOTH, part-15, or 802.11. “Part-15” refers to aconventional low-power, short-range wireless protocol, such as that usedin cordless telephones. Other communication protocols include a part 15low power short range radio, standard BLUETOOTH or BLUETOOTH Low Energyto conserve power or other low power short range communications means.The short-range wireless transmitter (e.g., a BLUETOOTH transmitter)receives information from the microprocessor and transmits thisinformation in the form of a packet through an antenna. An externallaptop computer or hand-held device features a similar antenna coupledto a matched wireless, short-range receiver that receives the packet. Incertain embodiments, the hand-held device is a cellular telephone with aBluetooth circuit integrated directly into a chipset used in thecellular telephone. In this case, the cellular telephone may include asoftware application that receives, processes, and displays theinformation. The secondary wireless component may also include along-range wireless transmitter that transmits information over aterrestrial, satellite, or 802.11-based wireless network. Suitablenetworks include those operating at least one of the followingprotocols: CDMA, GSM, GPRS, Mobitex, DataTac, iDEN, and analogs andderivatives thereof. Alternatively, the handheld device is a pager orPDA.

A general method is as follows. The light source 35 transmits lightthrough at least one artery of the user. The photo-detector 36 detectsthe light. The pulse rate is determined by the signals received by thephoto-detector 36.

This information is sent to the microprocessor for creation of user'sreal-time pulse rate. The microprocessor further processes theinformation to display pulse rate, calories expended by the user of apre-set time period, target zones of activity, time and/or dynamic bloodpressure. The information is displayed on a display member orelectro-optical display.

In a preferred embodiment, the article 25 has four control buttons 43a-d as shown in FIGS. 1 and 5. The control buttons 43 a-d are preferablypositioned in relation to the display member 40 to allow the userimmediate visual feedback of the user's inputted information. The middlecontrol button 43 b preferably activates and deactivates the article 25.The left button 43 a is preferably used to scroll through the differentmodes. The right button 43 c is preferably used to input data. Thecontrol buttons 43 a-d allow for the user's personal data to be enteredand for choices to be selected by the user. The left button 43 apreferably allows for the user's calories burned to be displayed on thedisplay member 40 and for the activity to be reset, and allows for otherfitness monitoring features to be displayed.

To activate the article 25, the middle button 43 b is depressed forpreferably 0.5 seconds and then released. The display member will appearwith a current pulse of the user and a calories burned display. Themicroprocessor preferably stores the calories burned and accumulates thevalues for a daily calories burned value and a total calories burnedvalue until the activity is reset.

To enter the user's personal data, the middle button 43 b is depressedfor 2 seconds and then released. The user will enter gender, age, mass,height and resting heart rate. Entering the data entails pushing themiddle button to select a category (gender, age, . . . ) and thenpushing the right or left button to scroll through the available optionsor to enter a value (e.g. age of the user). The middle button 43 b ispressed again to save the entry. This process is preformed until theuser's has entered all of the data that the user wishes to enter intothe microprocessor. The display member 40 will then display a heart rateand current calories burned value. A preset resting heart rate for menand women is preferably stored on the microprocessor, and used as adefault resting heart rate. However, the user may enter their ownresting heart rate value if the user is aware of that value. To accessdaily calories, the left button 43 a is pushed by the user and thedisplay member 40 will illustrate the value for daily calories burned bythe user. If the left button 43 a is pushed again, the value for totalcalories burned by the user will be displayed on the display member 40.The left button 43 a is pushed again to return to a heart rate value onthe display member 40.

The right button 43 c is pushed to scroll through the choices of otheroutput values, which comprises: basal metabolic rate; average heartrate; minimum heart rate; maximum heart rate; fat burn heart rateexercise target zone; cardio burn heart rate exercise target zone; and,summary of daily calories burned. The basal metabolic rate (displayed as“BMR”) is an estimate of the total calories burned by the user in oneday without exercise, and is based on the user inputted personal data.The average heart rate (displayed as “avHR”) is the average heart rateof the user between resets, and is an overall indicator of fitness. Thelower the average heart rate, the healthier the heart. The average heartrate is also a measure of the effectiveness of the exercise programemployed by the user since a decrease in the average heart rate of theuser will indicate the user's fitness has improved. The minimum heartrate (displayed as “mnHR”) of the user is typically measured duringsleep and periods of relaxation. The maximum heart rate (displayed as“mxHR”) is typically measured during intense workouts. The fat burnheart rate exercise target zone (displayed as “fatB”) displays a low andhigh range for the heart rate of the user to optimize fat burning duringexercise. The cardio burn heart rate exercise target zone provides ahigh and low range for the heart rate of the user to optimize cardioconditioning during exercise. The summary of daily calories burned(displayed as “cal”) displays the daily calories burned by the user.

In a preferred embodiment, the accelerometer is a multiple-axisaccelerometer, such as the ADXL202 made by Analog Devices of Norwood,Mass. This device is a standard micro-electronic-machine (“MEMs”) modulethat measures acceleration and deceleration using an array ofsilicon-based structures.

In yet another embodiment, the monitoring device 20 comprises a firstthermistor, not shown, for measuring the temperature of the user's skinand a second thermistor, not shown, for measuring the temperature of theair. The temperature readings are displayed on the display member 40 andthe skin temperature is preferably utilized in further determining thecalories expended by the user during a set time period. One suchcommercially available thermistor is sold under the brand LM34 fromNational Semiconductor of Santa Clara, Calif. A microcontroller that isutilized with the thermistor is sold under the brand name ATMega 8535 byAtmel of San Jose, Calif.

The monitoring device 20 may also be able to download the information toa computer for further processing and storage of information. Thedownload may be wireless or through cable connection. The informationcan generate an activity log or a calorie chart.

The microprocessor can use various methods to calculate calories burnedby a user. One such method uses the Harris-Benedict formula. TheHarris-Benedict formula uses the factors of height, weight, age, and sexto determine basal metabolic rate (BMR). This equation is very accuratein all but the extremely muscular (will underestimate calorie needs) andthe extremely overweight (will overestimate caloric needs) user.

The equations for men and women are set forth below:Men: BMR=66+(13.7×mass(kg))+(5×height(cm))−(6.8×age (years))Women: BMR=655+(9.6×mass)+(1.8×height)−(4.7×age)

The calories burned are calculated by multiplying the BMR by thefollowing appropriate activity factor: sedentary; lightly active;moderately active; very active; and extra active.

Sedentary=BMR multiplied by 1.2 (little or no exercise, desk job)

Lightly active=BMR multiplied by 1.375 (light exercise/sports 1-3days/wk)

Moderately Active=BMR multiplied by 1.55 (moderate exercise/sports 3-5days/wk)

Very active=BMR multiplied by 1.725 (hard exercise/sports 6-7 days/wk)

Extra Active=BMR multiplied by 1.9 (hard daily exercise/sports &physical job or 2× day training, marathon, football camp, contest, etc.)

Various target zones may also be calculated by the microprocessor. Thesetarget zones include: fat burn zone; cardio zone; moderate activityzone; weight management zone; aerobic zone; anaerobic threshold zone;and red-line zone.Fat Burn Zone=(220−age)×60% & 70%

An example for a thirty-eight year old female:

-   -   i. (220−38)×0.6=109    -   ii. (220−38)×0.7=127    -   iii. Fat Burn Zone between 109 to 127 heart beats per minute.        Cardio Zone=(220−your age)×70% & 80%

An example for a thirty-eight year old female:

-   -   i. (220−38)×0.7=127    -   ii. (220−38)×0.8=146    -   iii. Cardio zone is between 127 & 146 heart beats per minute.

Moderate Activity Zone, at 50 to 60 percent of your maximum heart rate,burns fat more readily than carbohydrates. That is the zone one shouldexercise at if one wants slow, even conditioning with little pain orstrain.

Weight Management Zone, at 60 to 70 percent of maximum, strengthens onesheart and burns sufficient calories to lower one's body weight.

Aerobic Zone, at 70 to 80 percent of maximum, not only strengthens one'sheart but also trains one's body to process oxygen more efficiently,improving endurance.

Anaerobic Threshold Zone, at 80 to 90 percent of maximum, improves one'sability to rid one's body of the lactic-acid buildup that leads tomuscles ache near one's performance limit. Over time, training in thiszone will raise one's limit.

Red-Line Zone, at 90 to 100 percent of maximum, is where seriousathletes train when they are striving for speed instead of endurance.

Example One

Female, 30 yrs old, height 167.6 centimeters, weight 54.5 kilograms.

The BMR=655+523+302−141=1339 calories/day.

The BMR is 1339 calories per day. The activity level is moderatelyactive (work out 3-4 times per week). The activity factor is 1.55. TheTDEE=1.55×1339=2075 calories/day. TDEE is calculated by multiplying theBMR of the user by the activity multiplier of the user.

The heart rate may be used to dynamically determine an activity leveland periodically recalculate the calories burned based upon that factor.An example of such an activity level look up table might be as follows:Activity/Intensity Multiplier Based on Heart Rate

Sedentary=BMR×1.2 (little or no exercise, average heart rate 65-75 bpmor lower)

Lightly active=BMR×3.5 (light exercise, 75 bpm−115 bpm)

Mod. active=BMR×5.75 (moderate exercise, 115-140 pm)

Very active=BMR×9.25 (hard exercise, 140-175 bpm)

Extra active=BMR×13 (175 bpm−maximum heart rate as calculated with MHRformula)

For example, while sitting at a desk, a man in the above example mighthave a heart rate of between 65 and 75 beats per minute (BPM). (Theaverage heart rate for an adult is between 65 and 75 beats per minute.)Based on this dynamically updated heart rate his activity level might beconsidered sedentary. If the heart rate remained in this range for 30minutes, based on the Harris-Benedict formula he would have expended1.34 calories a minute×1.2 (activity level)×30 minutes, which is equalto 48.24 calories burned.

If the man were to run a mile for 30 minutes, with a heart rate rangingbetween 120 and 130 bpm, his activity level might be considered veryactive. His caloric expenditure would be 1.34 calories a minute×9.25(activity level)×30 minutes, which is equal to 371.85.

Another equation is weight multiplied by time multiplied by an activityfactor multiplied by 0.000119.

FIG. 13 illustrates a block diagram of a flow chart of a signalprocessing method of the present invention. As shown in FIG. 10, thephotodetector 36 of the optical sensor 30 receives light from the lightsource 35 while in proximity to the user's artery. The light source 35is preferably a plurality of LEDs 35. The intensity of the light ispreferably controlled by an integrator 300. In a preferred embodiment,the optical sensor 30 is a TRS1755 which includes a green LED lightsource (567 nm wavelength) and a light-to-voltage converter. The outputvoltage is directly proportional to the reflected light intensity. Thesignal 299 is sent to the microprocessor. At block 1300, the signalacquisition is performed. In reference to FIGS. 14 and 15, in the pulsemode the LED 35 is periodically activated for short intervals of time bya signal from the microcontroller. The reflected pulse of light isreceived by the sensor, with the generation of a voltage pulse having anamplitude proportional to the intensity of the reflected light. When theLED is activated, the switch, SW, is open by the action of the controlsignal from the microcontroller, and the capacitor, C, integrates thepulse generated from the sensor by charging through the resistor R.Immediately prior to deactivation of the LED, the analog-to-digitalconverter acquires the value of the voltage integrated across thecapacitor, C. The analog-to-digital converter generates a data sample indigital form which is utilized by the microcontroller for evaluation ofthe heart rate the wearer. Subsequent to the sample being acquired bythe analog-to-digital converter, the LED is deactivated and thecapacitor, C, is shortcut by switch, SW, to reset the integrator, RC. Asignal indicating sensor saturation is also sent to the microcontrollerfor light control of the LEDs. This states remains unchanged for a giventime interval after which the process is repeated, which is illustratedin FIG. 15. The signals are shown in FIG. 15, with the raw sensor signalreceived from the sensor amplifier shown as varying between reflectedlight when the LEDs are on and an ambient light level when the LEDs areoff. The filtered signal from the high pass filter (“HPF”) is shown asthe filtered sensor signal in FIG. 14. The integrator reset signal isshown as integrator out signal in FIG. 15, and the integrator resetsignal in FIG. 14.

At block 1305, a band pass filter is implemented preferably with twosets of data from the analog-to-digital converter. At block 1305, anaverage of the values of data samples within each of a first set ofsamples is calculated by the microprocessor. For example, the values ofdata samples within forty-four samples are summed and then divided byforty-four to generate an average value for the first set of samples.Next, an average of the values of data samples within a second set ofsamples is calculated by the microprocessor. For example, the values ofdata samples within twenty-two samples are summed and then divided bytwenty-two to generate an average value for the second set of samples.Preferably, the second set of samples is less than the first set ofsamples. Next, the average value of the second set of samples issubtracted from the average value for the first set of samples togenerate a first filtered pulse data value.

At block 1310, the filtered pulse data value is processed using a heartrate evaluation code to generate a first heart rate value. In apreferred method, the heart rate evaluation code obtains the heart rateby calculating the distance between crossing points of the voltagethrough zero. Once the first heart rate value is known, then an adaptiveresonant filter is utilized to generate a filtered second heart ratevalue by attenuating interference caused by motion artifacts. At block1315, a sample delay is computed as the period of evaluated heart ratedivided by two.

At block 1320, preferably a two cascade adaptive resonant filtergenerates a second filtered pulse data value which is processed at block1310 using the heart rate evaluation code to generate a second heartrate value. Those skilled in the pertinent art will recognize thatthree, four, or more, cascade adaptive resonant filters may be utilizedin generating the second filtered pulse data value. Essentially, thehighest and lowest values are disregarded in calculating the filteredsecond heart rate value. Alternatively, a phase is established and anyvalues outside of the phase are disregarded in calculating the secondheart rate value. The filtering is preferably continued during the useof the monitor thereby further refining the heart rate value of theuser.

A motion sensor 1100 is included to assist in identifying motion noiseand filtering the noise from the signal sent by the sensor 30. Themotion sensor 1100, such as an accelerometer, is integrated into thecircuitry and software of the monitoring device 20. As the motion sensordetects an arm swinging, the noise component is utilized with the signalprocessing noise filtering techniques to provide additional filtering toremove the noise element and improve the accuracy of the monitoringdevice 20. More specifically, the signal from the optical sensor 30 istransmitted to the processor where a custom blood pressure filter 41 wprocesses the signal which is further processed at by custom adaptivefilter 41 x before being sent to a heart beat tracking system 41 y andthen transmitted to a heart rate beat output 41 z. The heart rate beatoutput 41 z provides feedback to the custom adaptive filter 41 x whichalso receives input from the motion sensor 1100.

FIG. 17 is a preferred method 500 for controlling the light intensity ofthe optical sensor 30. At block 505, the light intensity of the lightsource 35 is monitored. At block 510, the sensor/photodetector isdetermined to be saturated by the light source. At block 515, theintensity of the light source is modified by adjusting the resistanceand the flow of current to the light source 35. At block 520, the lightintensity is again monitored and adjusted if necessary. In a preferredembodiment, this automatic gain mechanism prevents the green light fromoverwhelming the photodetector 36 thereby maintaining an accuratereading no matter where the optical sensor is placed on the user.

FIG. 16 illustrates how the control mechanism operates to maintain aproper light intensity. As the signal reaches the upper limit, thephotodetector becomes saturated and the processor lowers the currentflow, which results in a break in the signal. Then as the signal islowered it becomes too low and the processor increases the lightintensity resulting in a break in the signal.

A block diagram for vital sign signal processing is shown in FIG. 18.The optical sensor 730 is placed on or near an artery 90 of a user ofthe monitoring device 20. The optical sensor 730 has a pair of LEDs 735and a photodetector 736, which receives reflected light 737 from theLEDs 735. The microprocessor 741 has a LED control 715 connected to DAC702 for controlling the intensity of the LEDs 737. The signal from thephotodetector 736 is transmitted to a high pass filter (HPF) 703 whichsends it to an analog to digital converter 704, and the signal from thephotodetector 737 is also sent directly to a second analog to digitalconverter 704. The real-time signal is then sent to a sensor dataevaluation 714 to provide feedback to the LED control 715, and then isalso sent to the filter of the signal processing for mitigations ofnoise and heart rate evaluations 712. Simultaneously, the accelerometer710 transmits X-axis, Y-axis and Z-axis signals for the motion of themonitoring device 20 to an accelerometer data evaluation 711 of themicroprocessor 741. This signal is then sent to the signal processingfor mitigations of noise and heart rate evaluations 712. The output forthe heart rate and/or calories is generated at block 713 of themicroprocessor 741, which then sends the results to the display 740.

FIG. 19 illustrates a prior art signal processing of a vital signwithout the use of an accelerometer to filter the signal. As shown inFIG. 19, sensor data at block 2100 is sent to a band pass filter 2110and then to a comb filter 2115 and to a heart rate evaluator 2125through a switch 2120. Feedback from the heart rate evaluator 2125 issent to comb filter 2115, such as described in Brady et al., U.S. Pat.No. 7,468,036 for a Monitoring Device, Method And System, which ishereby incorporated by reference in its entirety.

FIG. 20 illustrates signal processing of a vital sign with the use of anaccelerometer to filter the signal. As shown in FIG. 20, sensor data atblock 2100 is sent to a band pass filter 2110 and then to a comb filter2165 for noise suppression, then to a Comb filter for a heart rate 2215and to a heart rate evaluator 2125 through a switch 2120. Feedback fromthe heart rate evaluator 2125 is sent to comb filter 2115. However,accelerometer data from block 2150 is sent to an array of Comb filters2155, then to a selection of a filter delay for mitigation of mechanicalnoise at 2160 and then to comb filter 2165 for noise suppression in thevital sign signal from the vital sign sensor.

FIG. 21 illustrates a type 2 Comb filter 3100 which is preferably usedas the Comb filter for noise suppression 2165 of FIG. 20. The signalsbegin at input 3110. A delay is generated at 3120, sent to interpolator3125 and gain 3130 and then a filter delayed signal is sent from output3135.

FIG. 22 illustrates a type 1 Comb filter 3200 which is preferably usedas the Comb filter for the heart rate 2115 of FIG. 20. The signals beginat input 3210. A delay is generated at 3225, sent to interpolator 3220and gain 3215 and then a filter delayed signal is sent from output 3230.

FIG. 23 illustrates a four cycle Comb filter 3300 with a filter delay of8, 12, 16, . . . , 4N, which is preferably used as at least one of thearray of Comb filters 2155 of FIG. 20. The signals begin at input 3310.A collector 3335 sums the signals. A counter 3330 transmits signals tothe collector and interpolator 3320. A delay is generated at 3325, sentto the interpolator 3320 and gain 3315 and then a filter delayed signalis sent from output 3340.

FIG. 24 illustrates a four cycle Comb filter 3400 with a filter delay of10, 14, 18, . . . , 4N+2, which is preferably used as at least one ofthe array of Comb filters 2155 of FIG. 20. The signals begin at input3410. A collector 3435 sums the signals. A counter 3430 transmitssignals to the collector and interpolator 3420. A delay is generated at3425, sent to the interpolator 3420 and gain 3415 and then a filterdelayed signal is sent from output 3440.

FIGS. 9-11 illustrate the sensor 30. The sensor 30 has a photodetector36, at least two LEDs 35 and an opaque light shield 57. The LEDs 35 arepreferably green light LEDs. The sensor 30 preferably has a length, L,of 7-10 mm on each side, as shown in FIG. 9. The sensor 30 preferablyhas a height, H, of 1-1.5 mm, as shown in FIG. 10. The opaque lightshield 57 blocks the direct light from the LEDs 35 to the photodetector36. Only the green light diffused and translucent through the media(skin of the user) 61, as shown in FIG. 11, is allowed to enter thechamber of the photodetector 36. This provides for a more accurate heartrate or vital sign signal.

In a preferred design of the sensor 30, the distance between the centersof active areas of LEDs 35 is preferably 5-6 mm. The active area(photodetector 36) of a sensor 30 is placed in the middle of thatdistance. In the custom sensor, the distance of a custom sensor ispreferably in the range of 3-4 mm (which means the spacing between thecenters of photodetector 36 and LEDs 35 is about 1.5-2 mm). The distanceis preferably sufficient for the placement of an opaque barrier betweenthem. To control the amplitude of the LED intensity pulse a sufficientcurrent (voltage) range of intensity ramp is used to control the LEDs 35and to achieve the same levels of intensity in both LEDs 35 within agiven range. The electrical characteristics of 520 nm SunLED in terms ofvoltage range for intensity ramp is sufficient. The top surface of thesensor 30 is preferably flat and in steady contact with the skin. Undera strong motion condition, the skin moves at the border of the contactsurface. The sizes of the sensor area and flat skin contact area areselected to reduce the border motion effects. If the distance betweenthe LEDs and sensor is reduced, a lighted area of the skin is smaller,and the contact area is reduced (5×5 mm is acceptable). LGA enables aneasy way to seal the contact area from moisture. The preferredembodiment uses 250 microsecond LED pulses and a 12T photodetector 36with second order active high pass filter (100 Hz cutoff). The DC outputof the sensor 30 is monitored to ensure that it is not saturated by theeffects of ambient light. The use of short-term pulses reduces ambientlight. In the preferred embodiment, voltage is collected at the sensoroutput every 2 msec. Inside the microprocessor 741, an average 8consecutive samples improve the SNR (signal to noise ratio) and thenwork with the averaged numbers. Therefore the sampling rate for raw datais preferably 2 msec, however if 8-samples averaging is utilized in theintegrated sensor the data output rate is reduced to sending a newaveraged value every 16 msec. An ADC is used with a 12-bit resolution.The response of TSL12T is acceptable. 100 Hz is the low limit for LPFcutoff. The selection of pulse duration is preferably based on the speedof the LED drivers, sensor electronics and output pick detection. Thehigher the low frequency cutoff that is implemented for the selectedpulse duration, the better SNR.

Preferably, two reactance circuits work as load resistances for aphotodiode, BPW34. The voltage drop at each reactance circuit isamplified by a differential amplifier, built with two 2N4416 FETs. Thesymmetrical design makes a diode bias voltage of about 2 V, which isnearly independent of ambient light conditions. The circuit isinsensitive to common mode interference. The circuit operates using asingle 5 volt power supply.

FIG. 12 is a functional block diagram for the signal processing 2000 ofthe sensor. A trigger input 2001 has a duration of 50-250 microsecondsand a period of 2 milliseconds for input to a pulse generator 2004,which also receives input from VDD 2002. Input voltage for intensitycontrol 2003 is sent to resistors 2005 and 2006 and to LEDs 2007 and2008 and activated by switch 2009. Ambient light filter and amplifier2010 transits to synchronized pick detector 2012 for a voltage or dataoutput 2014 as an output signal 2016.

As shown in FIGS. 25-28, the system includes a monitoring device 20 anda mobile communication device 1520. The monitoring device 20 transmitsdata 1515 to the mobile communication device 1520 for display on ascreen 1525 of the mobile communication device 1520. The user 1800preferably wears both the mobile communication device 1520 and themonitoring device 20. Such a mobile communication device preferablyincludes the IPHONE® smartphone or IPAD™ tablet computer, both fromApple, Inc., BLACKBERRY® smartphones from Research In Motion, theANDROID® smartphone from Google, Inc., the TRE® smartphone from Palm,Inc., and many more.

One aspect of the present invention is a system for monitoring at leastone vital sign of a user. The system comprises a smartphone and amonitoring device. The smartphone comprises a short range wirelesstransceiver, a processor and a display screen. The monitoring devicecomprises a housing, an optical sensor for measuring blood flow throughan artery of a wrist, arm or ankle of the user, a processor, a shortrange wireless transceiver, and a power source. The short range wirelesstransceiver operates on a communication protocol using a 9 kHzcommunication format, a 125 kHz RFID communication format, a 13.56 MHzcommunication format, a 433 MHz communication format, a 433 MHz RFIDcommunication format, or a 900 MHz RFID communication format.

Another aspect of the present invention is a method wherein themonitoring device transmits raw data from the optical sensor and themotion sensor to mobile communication device for processing using asignal processing algorithm such as discussed in reference to FIG. 10.

Another aspect of the present invention is a method wherein themonitoring device performs a first filtering of the signals beforetransmitting the filtered data to the mobile communication device forfurther processing.

The system and method described herein may be used with an interactivegame such as disclosed in Hunt et al., U.S. patent application Ser. No.13/021,749, filed on Feb. 5, 2011 for a Monitoring Device For AnInteractive Game, which is hereby incorporated by reference in itsentirety.

A smartphone 1501 receives signals from a heart rate monitor (“HRM”) andthe display of the smartphone is used to view a user's heart rate (“HR”)and to work out to apps and to store data. The HRM simply outputs HR andaccelerometer data to the smartphone where a mobile application software(“HRM SW”) is processed by the powerful processor of the smartphone. All“heavy” processing and memory is conducted on the smartphone. Thisreduces the cost, size and power requirements of monitoring device andallows for the more powerful offboard processing, display and storage ofHR data by the smatphone. The software application might be a purefitness app, might be provided by WEIGHT WATCHERS to their clients as anapp or could be a game or even medical application for in home use. Thegame might also require that heart rate reach a certain high or lowtarget before being able to conduct a specified in-game action. Forexample, a user might have to restore heart rate to their restingbaseline before being able to do a high jump. Similarly, they might haveto enter a higher target heart zone to “power up” for an attack. HRMapplication for video game overview: A heart rate monitor would be usedas an integral, interactive element of video games to add a degree ofrealism. A basic example would be in a game that required shootingskills or skills that could be enhanced or degraded by a physical stateas indicated by heart rate level. A player's normal heart rate would bemeasured and entered into a game data base. This average would be usedas a baseline to provide more accurate shooting or combat skills if theheart rate was at a lower level during the activity and accuracy wouldbe degraded if the HR was at a certain level above the average. This isreflective of the real world where actual snipers use heart rate as ameans to achieve better accuracy. It also is reflective of the realworld where a person has to physically move and evade and then fireaccurately or engage in other physical combat using manual weapons orpersonal combat skills. This technique could also be used in sportsgames such as golf games where shot accuracy could be improved by alower heart rate or conversely adversely affected by an elevate HRreflecting a nervous or agitated state. The game could encourage andpromote the use of interactive biofeedback to control the heart rate andimprove performance. In this case the biofeedback training couldtranslate into real world applications for sports or other activities.This application of HR monitoring technology requires a real time heartrate monitor. Such a device may detect the electrical pulses from theheart such as the chest belt monitors, however a preferred applicationwould be a more convenient monitor that would be worn on the arm of thegame player, but would be motion resistant as well as continuous.

The communications from the monitoring device to the smartphone ispreferably accomplished by using a part 15 low power short range radio,standard Blue tooth or Blue Tooth Low Energy to conserve power or otherlow power short range communications means. For mobile phones and mobilephone applications the HRM is preferably interactive with Windowsoperating systems, Apple Operating systems or emergent operating systemssuch as Android. This facilitates the broadest use in home and in mobileapplications.

The monitoring device preferably transmits raw heart rate andaccelerometer data to a smartphone. The data is preferably stored orreal-time data.

A smartphone application preferably interprets data, displays, andstores it. Such data might include items like heart rate, caloriesburned, exercise time, max/min/average heart rate, and others. Thisallows for use of the greater processing power on the smartphone.

Alternatively the monitoring device transmits interpreted data: heartrate, caloric burn exercise session information, exercise time,max/min/average HR info, etc.

The monitoring device alternatively has a display and transmits rawheart rate and accelerometer data to Smart Phone. This may be stored orreal-time data.

In this embodiment, the monitoring device displays some data on adisplay of the monitoring device.

The smartphone application interprets data, displays, and stores it.Such data might include items like heart rate, calories burned, exercisetime, max/min/average heart rate, and others. This allows for use of thegreater processing power on the smartphone.

Alternatively the monitoring device transmits interpreted data: heartrate, caloric burn exercise session information, exercise time,max/min/average HR info, etc.

A user can run or do other exercise while wearing the monitoring deviceand the smartphone. The smartphone then becomes a “mobile exercisedevice.

Users may receive on screen instructions that adjust related to heartrate activity. Instructions may ask user to perform actions whichincrease/decrease HR.

From the foregoing it is believed that those skilled in the pertinentart will recognize the meritorious advancement of this invention andwill readily understand that while the present invention has beendescribed in association with a preferred embodiment thereof, and otherembodiments illustrated in the accompanying drawings, numerous changesmodification and substitutions of equivalents may be made thereinwithout departing from the spirit and scope of this invention which isintended to be unlimited by the foregoing except as may appear in thefollowing appended claim. Therefore, the embodiments of the invention inwhich an exclusive property or privilege is claimed are defined in thefollowing appended claims.

We claim as our invention the following:
 1. A system for monitoring areal-time vital sign of a user, the system comprising: a monitoringdevice comprising an optical sensor for generating a real-time digitizedoptical signal corresponding to a flow of blood through an artery of theuser, the optical sensor comprising a photodetector, a first LEDemitting a green light, a second LED emitting a green light at the samewavelength of the first LED, and an opaque light shield, the opaquelight shield preventing the photodetector from receiving direct lightfrom the first LED or the second LED, and only allowing green lightdiffused and translucent through a skin of the user to be received bythe photodetector, wherein the photodetector is positioned an equaldistance from the first LED and the second LED, wherein thephotodetector is positioned between the first LED and the second LED,wherein the opaque light shield encircles the first LED in a firstchamber, the opaque light shield encircles the photodetector in a secondchamber, and the opaque light shield encircles the second LED in a thirdchamber; an accelerometer for generating a real-time accelerometer datacomprising an X-axis signal, a Y-axis signal and a Z-axis signal basedon a movement of the user; and a first transceiver for transmitting thereal-time digitized optical signal and the real-time accelerometer datafrom the monitoring device; a mobile communication device comprising asecond transceiver for receiving the real-time digitized optical signaland the real-time accelerometer data from the monitoring device, aprocessor in electrical communication with the second transceiver, theprocessor configured to receive the real-time digitized signal and thereal-time accelerometer data, the processor configured to generate areal-time heart rate for the user, wherein the processor is configuredto filter motion noise from the digital signal utilizing the signal fromthe accelerometer, process the digital signal to obtain an average pulsevalue of a first set of time periods, process the digital signal toobtain an average pulse value of a second set of time periods, thesecond set of time periods less than the first set of time periods,subtract the average pulse value of the second set of time periods fromthe average pulse value of the first set of time periods to generate afirst filtered pulse data value, process the first filtered pulse datavalue to obtain a first heart rate value, and use the first heart ratevalue to filter the subsequent average pulse values generated from thedigital signal to obtain a real-time heart rate value of the user, and adisplay for displaying the real-time heart rate value for the userreceived from the processor.